Low-pass EMI filters are widely used to suppress interference. Such filters have used multilayer capacitors in the form of surface mount chip capacitors, and entire EMI filters have been available as surface mount chips.
One example of an electronic chip is an EMI filter for interference suppression within a motor housing. It is known to mount such a filter directly within a conductive outer casing for a motor as in automotive applications. There may be as many as 100 motors in a present luxury automobile. The RF emissions of DC motors are a significant problem, as an electrical motor is a noisy RF source that can easily interfere with other electronic devices through common and differential mode noise on the power lines. For noise above a certain frequency on the power lines, the power lines tend to act as an antenna and radiate energy into free space. Substantial RF noise is generated from a small DC motor by the high speed switching which occurs at angular velocities as high as 24,000 rpm at 12 V DC. EMI filters are used to suppress the RF noise at the source.
One known layout for a chip capacitor EMI filter comprises a rectangular casing, with connections at each end wall and connections at opposite side walls. These connections are for example tin-lead coating layers. This chip is typically soldered into a carrier provided with the motor housing. In motor applications, there are particularly harsh environmental demands, and the installation must be able to withstand large thermal shock as well as technical vibration. The conventional mounting technique may not meet these demands.